import java.util.Scanner;
public class Test4{
    public static void main(String[] args){
        Scanner scanner = new Scanner(System.in);
        int n=scanner.nextInt();
        int j=0;
        if(n==1){
            System.out.println(n+" is not a prime number.");
        }else{
        for(int i=2;i<n;i++){
            if(n%i==0){
                j++;
            }
        }if(j>0){
            System.out.println(n+" is not a prime number.");
        }else System.out.println(n+" is a prime number.");
        }scanner.close();
    }
}